Electric grinding machine

Abstract

An electric grinding machine includes a spindle to be driven with a motor; a grinding disc attached to the spindle; a cover covering the grinding disc; a window disposed on the cover to expose an outer circumference of the grinding disc; a hinge mechanism joining the window to the cover so that the window freely moves between an opened position and a closed position, said hinge mechanism having a rotational axis disposed on the cover; a gate protruding from the window and having a cylindrical portion concentrical to the rotational axes; a hollowed portion formed in the gate, said hollowed portion forming a passage opening between the cover and the cylindrical portion when the window is closed; a slider disposed on the cover, said slider passes through the passage opening to hold the window in the closed position; and a piston spring urging the slider toward the window.

What is claimed is: 
     
       1. An electric grinding machine comprising:
 a spindle to be driven with a motor extending in a first direction; 
 a grinding disc attached to the spindle; 
 a cover covering the grinding disc; 
 a window disposed on the cover to expose a part of an outer circumference of the grinding disc; 
 a hinge mechanism extending in a second direction intersecting the first direction and joining the window to the cover so that the window freely moves between an opened position and a closed position; and 
 a gate structure comprising:
 a solid rod member which extends in the second direction and is concentric with a rotational axis of the hinge mechanism when the window is in the opened position and in the closed position; wherein the solid rod member comprises a planar longitudinal outer surface extending in the second direction and an outer circled circumferential surface extending in the second direction; 
 a passage opening which extends in the second direction and is formed by an upper surface of the cover and the planar longitudinal surface of the solid rod member, when the window is in the closed position; 
 a slider configured to pass through the passage opening in a third direction intersecting the second direction and the first direction, wherein the window moves to the opened position from the closed position when the slider passes through the passage opening from a side of the window to a side of the cover, and wherein the window moves to the closed position from the opened position when the slider passes through the passage opening from the side of the cover to the side of the window; and 
 a coil spring urging the slider towards the window in the third direction. 
 
 
     
     
       2. The electric grinding machine according to  claim 1 , further comprising a torsion spring which is disposed around the rotational axis of the hinge mechanism and urges the window towards the opened position. 
     
     
       3. The electric grinding machine according to  claim 1 , wherein said window includes a vent to be covered with the slider when the slider passes through the passage opening in the third direction from the side of the cover to the side of the window so that the window is in the closed position. 
     
     
       4. The electric grinding machine according to  claim 1 , wherein said slider includes a thin plate portion at one distal end thereof which is closer to the window than the cover, and the thin plate portion is configured to pass through a gap formed by the upper surface of the cover and an outer circled circumferential surface of the solid rod member, when the window is in the opened position. 
     
     
       5. The electric grinding machine according to  claim 1 , wherein said cover includes a groove, and said window includes a packing to be fitted in the groove when the window is in the closed position. 
     
     
       6. The electric grinding machine according to  claim 1 , wherein said slider includes a slope portion at another distal end thereof which is closer to the cover than the window, and the slope portion has greater thickness at a portion which is closer to the cover than the window. 
     
     
       7. The electric grinding machine according to  claim 1 ,
 wherein, when the window is in the closed position, the upper surface of the cover and the planar longitudinal surface of the solid rod member forms the passage opening, and 
 wherein, when the window is in the closed position, the planar longitudinal surface of the solid rod member faces the slider. 
 
     
     
       8. The electric grinding machine according to  claim 1 ,
 wherein, when the window is in the opened position, the upper surface of the cover and the outer circled circumferential surface of the solid rod member forms a gap, and 
 wherein, when the window is in the opened position, the outer circled circumferential surface of the solid rod member faces the slider. 
 
     
     
       9. The electric grinding machine according to  claim 1 ,
 wherein the slider comprises:
 a thin plate portion at one distal end of the slider which is closer to the window than the cover; 
 a lever at another distal end of the slider which is closer to the cover than the window; and 
 a main plate portion which has a thickness thicker than a thickness of the thin plate portion and is located between the thin plate portion and the lever. 
 
 
     
     
       10. The electric grinding machine according to  claim 9 ,
 wherein the slider further comprises a slope portion which is located on the main plate portion. 
 
     
     
       11. The electric grinding machine according to  claim 10 ,
 wherein the slope portion has greater thickness at a portion which is closer to the cover than the window. 
 
     
     
       12. The electric grinding machine according to  claim 10 ,
 wherein the slider further comprises another slope portion which is located between the main plate portion and the thin plate portion. 
 
     
     
       13. The electric grinding machine according to  claim 9 ,
 wherein, when the window is in the closed position, the upper surface of the cover and the planar longitudinal surface of the solid rod member forms the passage opening, and 
 wherein, when the window is in the closed position, the planar longitudinal surface of the solid rod member faces the main plate portion of the slider. 
 
     
     
       14. The electric grinding machine according to  claim 9 ,
 wherein, when the window is in the opened position, the upper surface of the cover and the outer circled circumferential surface of the solid rod member forms a gap, and 
 wherein, when the window is in the opened position, the outer circled circumferential surface of the solid rod member faces the thin plate portion of the slider.